Effects Of Environmental Factors On The White Spot Disease Transmission In Penaeid Shrimp And Molecular Biomarker System In Mussels

We studied the possible role that marine microalgae played during the outbreaksof WSS (white spot syndrome) and effects of two anionic surfactants sodiumdodecylbenzene sulfonate (SDBS) and sodium dodecyl sulfate (SDS) on molecularbiomarker system in Mytilus galloprovincialis under chronic exposure under chronicexposing (72 d).1. Effect of marine microalgae on white spot syndrome virus transmittingIn order to elucidate the possiblility of marine microalgae carrying WSSV (whitespot syndrome virus), six marine microalgae (Isochrysis galbana,Skeletonemacostatum,Chlorella sp.,Heterosigma akashiwo,Scrippsiella trochoidea,Dunaliellasalina) were co-cultured with adult Marsupenaeus japonicus infected with WSSV andwere assayed daily by nested-PCR to study whether they could carry WSSV. Furtherexperiments were conducted to investigate whether the virus carried by microalgaecould re-infect juvenile M. japonicus. Detection results on microalgae showed that allof the experimental microalgae could carry WSSV except H. akashiwo, and amongthem, Chlorella sp. and S. trochoidea especially had the strongest WSSV-carryingability. However, unlike other invertebrate carriers of WSSV, the detection results ofWSSV in microalgae were negative after 10 days of incubation. WSSV detectionresults in juvenile M. japonicus showed that the juvenile shrimp were re-infected byco-cultured Chlorella sp., notwithstanding, the juvenile M. japonicus carried so smallan amount of WSSV that it could only be detected by nested-PCR. The results of thisexperiment suggest that microalgae might be one possible horizontal transmissionpathway for WSSV. Further research, however, is required to better understand thefactors behind the different carrying abilities and virus-carrying mechanisms ofdifferent microalgae.2. Effect of anionic surfactants on molecular biomarker system in MytilusgalloprovincialisIn May and August 2003, we investigated anionic surfactants concentration inJiaozhou Bay,China. Two anionic surfactants sodium dodecylbenzene sulfonate(SDBS) and sodium dodecyl sulfate (SDS) were selected as contaminants to detecttheir effects on the biochemical indice and genotoxicological index in Mytilusgalloprovincialis. Results show that after 72 days exposing, activities of superoxidedismutase (SOD), catalase (CAT) and induced nitric oxide synthase (iNOS) weresignificantly inhibited by challenged SDBS (except CAT activity in 0.1mg/L group).the activities of reduced glutathione (GSH),glutathione-S-transferase (GST) andglutathione peroxidase (GPx) were significantly higher than their correspondingcontrol groups under 3.0 mg /L SDS and SDBS. Biochemical indice in Mytilusgalloprovincialis were more easily effected by SDBS than by SDS. Statistical analysissuggested that significant positive relationships were found between GST and GPx,iNOS and SOD. But negetive relationships were found between GSH and CAT,GSHand SOD under SBDS exposing. There is a significant positive relationship betweenSDS concentration and GST activity, but a negtivie relationship between SDBSconcentration and CAT activity. iNOS activity in the posterior adductor muscle maybe a promising exposed biomarker in Mytilus galloprovincialis for anionic surfactantsexposure. Statistical analysis based on AFLP profile showed that at the concentrationof SDS and SDBS used in the present work , a greater genotoxic effect was observedfor SDBS than for SDS. In addition, a different polymorphic profile was obtainedfrom different substances, these considerations indicated that DNA damages isdifferent for each substance. Results show that anionic surfactants can havesignificant effects on a group of biomarkers such as SOD, CAT, GSH, GPx, GST,iNOS and AFLP profile in Mytilus galloprovincialis under chronic exposing (72 d).